Re: add more frame types in window functions (ROWS)

2009/11/15 Andrew Gierth <andrew@tao11.riddles.org.uk>:
> My thinking is that the executor definitely shouldn't be relying on it
> being a specific node type, but should just ExecEvalExpr it on the
> first call and store the result; then you don't have to know whether
> it's a Const or Param node or a more complex expression.

Yeah, so that we allow something like ROWS BETWEEN 1 + $1 PRECEDING
AND ... And to support RANGE BETWEEN n PRECEDING ..., we should make
datum to add or to subtract from current value on initial call anyway.

Regards,


-- 
Hitoshi Harada